We have the next information
Let X be the number of customer purchased coffee
Let Y be the number of customer pwho urchased donuts
X∩Y Then is the number of customers who purchased both coffee and donuts
X∪Y is the number of customers who purchased both coffee or donuts
The number of customers who purchase only coffee is
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48 customers purchased only coffee
The number of customers who purchase only donuts is
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22 customers purchased only donuts
In order to know how many customers did not purchase either of these items
First we will calculate the customers that purchase something

then we know that the total number of customers is 110

21 customers did not purchase either of these items